The present invention relates to non-destructive inspection (NDI) instruments, and more particularly to an intelligent eddy current array probe which contains an embedded memory storage element for storing probe specific firing sequence information and transmitting the same to an NDI system upon connection of said array probe.
Any discussion of the related art throughout this specification should in no way be considered as an admission that such art is widely known or forms a part of the common general knowledge in the field.
Eddy current inspection is a well known NDI technique used to examine conductive materials. In a typical eddy current inspection operation, an eddy current array probe, comprising a plurality of coils, is placed adjacent to the surface of a material under inspection. At the start of an inspection operation, an NDI instrument coupled to said eddy current array probe energizes one or more coils within the array. This, in turn, induces a current in the material under inspection. One or more coils within the probe array then sense this induced current and provide a measurement signal to the NDI instrument. By measuring the current induced in a material under inspection, the impedance of said material can be calculated. Further, by tracking the impedance of a material under inspection as the probe is moved along the surface of said material (or, in some NDI operations, comparing the measured impedance to that of a stored reference), flaws and defects within said material can be found and analyzed.
In many advanced eddy current inspection operations, the individual coils of an eddy current array probe are energized and sensed in a specific sequence. This sequence, commonly referred to as a firing sequence, improves the efficiency and quality of an eddy current inspection. Typically, an NDI eddy current instrument will have a limited number of generator elements (used to energize the coils of the array probe) and a limited number of receiver elements (used to measure the induced currents sensed by the coils of the array probe). As such, an eddy current inspection operation making use of a firing sequence typically uses a multiplexer unit situated between an NDI instrument and an array probe to couple and decouple the individual coils of said array probe to the generator and receiver elements within said NDI instrument in accordance with the needs of a firing sequence devised for a given inspection operation.
An inspection operation on a cylindrical test piece, for example, would typically use an eddy current array probe with coils arranged circumferentially in a ring about said test piece. The firing sequence for such an inspection operation is directly dependent on the number of coils within the eddy current array probe being used to evaluate the tube. As different diameter test pieces are inspected, different eddy current array probes—with differing numbers of coils arranged in rings of differing diameters—are used such that the inspection operation can be optimized. Within such an inspection operation, each eddy current array probe used with the NDI system will require that the NDI instrument—or, in the case of some more advanced NDI systems, the programmable multiplexer used to couple the array probe to the NDI instrument—be prepared with a specific firing sequence optimized for that probe.
In prior art systems, preparing such an NDI system with a probe specific firing sequence requires that an additional step be performed when switching between different eddy current array probes. Such secondary steps include, but are not limited to, manually entering a new firing sequence algorithm into the system, adjusting connections between the instrument or multiplexer and the array probe by using different cablings, connector adapters, and the like, or wiring in different hardware components (such as a multiplexer specifically designed to function with a specific array probe and a specific inspection operation). These additional steps within an NDI operation can often be tedious, time consuming, require additional hardware to be available, negatively affect NDI system reliability, and introduce opportunities for error within said inspection operation.
Accordingly, it would be advantageous to provide an eddy current array probe for an NDI operation which did not require that a probe specific firing sequence be manually entered into the system by an operator.